Fastener stringer with tubular filament element

Abstract

A slide fastener has coupling elements secured to adjacent edges of a pair of carrier tapes wherein each of the elements is formed from a tubular filament by plastic deformation of selected portions, thus defining head portions, leg portions and connecting portions wherein the tubular filament has a ratio of filament wall thickness divided by the average inside diameter in the range of about 0.65 to about 1.8.

What is claimed is: 
     
       1. A stringer for a slide fastener comprising a tape-like supporting portion;   a coupling element formed from a continuous tubular deformable filament secured to an edge of the supporting portion;   said coupling element including a plurality of successive deformed convolutions of the continuous tubular deformable filament;   each of said convolutions having a head portion, a pair of leg portions extending from opposite sides of the head portion, and a connecting portion interconnecting leg portions of adjacent convolutions;   said continuous tubular deformable filament having a hollow core substantially throughout its length wherein the ratio of the average filament wall thickness divided by the average inside diameter is in the range of about 0.65 to about 1.8,   at least one of said head portion and said pair of leg portions of each convolution having a cross sectionally deformed portion whereat the wall of the tubular filament is collapsed into the hollow core such as to produce substantially cancelling tension and compression forces longitudinally in the filament to prevent any substantial elongation of the filament,   one of said pair of leg portions of each convolution extending over a side of the tape-like supporting portion and having a notch formed therein facing away from the tape-like supporting portion,   said stringer including a thread extending around the one leg portion of each convolution and laying in the notch of each convolution to secure the coupling element to the tape-like supporting portion, and   said notch of each convolution being formed by collapse of a portion of the wall of the tubular filament into the hollow core of the filament.   
     
     
       2. A stringer for a slide fastener comprising a tape-like supporting portion;   a coupling element disposed along one edge of the tape-like supporting portion and formed from a continuous tubular deformable filament having a hollow core substantially throughout its length;   said coupling element including a plurality of successive deformed convolutions of the tubular filament;   each of said convolutions having a head portion, a pair of leg portions extending from opposite sides of the head portion, and a connecting portion interconnecting leg portions of adjacent convolutions;   at least one of said head portion and said pair of leg portions of each convolution having a cross-sectionally deformed portion whereat the wall on only one side of the tubular filament is collapsed into the hollow core; and   said wall of the tubular filament being collapsed such as to produce substantially cancelling tension and compression forces longitudinally in the filament to prevent any substantial elongation of the filament.   
     
     
       3. A stringer for a slide fastener as claimed in claim 2 wherein the tubular filament has a ratio of average filament wall thickness divided by average inside diameter of approximately 0.9. 
     
     
       4. A stringer for a slide fastener as claimed in claim 2 wherein the tubular filament has a ratio of average filament wall thickness divided by average inside diameter in the range of about 0.65 to about 1.8. 
     
     
       5. A stringer for a slide fastener as claimed in claim 2 wherein one of said pair of leg portions of each convolution extends over a side of the tape-like supporting portion and has a notch formed therein facing away from the tape-like supporting portion,   said stringer includes a thread extending around the one leg portion of each convolution and laying in the notch thereof to secure the coupling element to the tape-like supporting portion, and   said notch of each convolution is formed by collapse of a portion of the wall on only one side of the tubular filament into the hollow core of the filament.   
     
     
       6. A stringer for a slide fastener as claimed in claim 2 wherein the tubular filament forming the coupling element includes a cross section having a circular periphery. 
     
     
       7. A stringer for a slide fastener as claimed in claim 6 wherein the cross section of the tubular filament has a circular opening concentric with the circular periphery. 
     
     
       8. A stringer for a slide fastener as claimed in claim 6 wherein the tubular filament forming the coupling element has a hollow core which is triangular shaped in transverse section. 
     
     
       9. A stringer for a slide fastener as claimed in claim 6 wherein the tubular filament forming the coupling element has a hollow core which is elliptical in transverse section. 
     
     
       10. A stringer for a slide fastener as claimed in claim 6 wherein the tubular filament forming the coupling element has a hollow core which is star-shaped in transverse section. 
     
     
       11. A stringer for a slide fastener as claimed in claim 2 wherein the tubular filament forming the coupling element has a cross section with a D-shaped periphery. 
     
     
       12. A stringer for a stringer as claimed in claim 11 wherein the tubular filament forming the coupling element has a hollow core of elliptical cross section. 
     
     
       13. A stringer as claimed in claim 2 wherein the tubular filament forming the coupling element has a cross section with an elliptical shaped periphery. 
     
     
       14. A stringer for a slide fastener as claimed in claim 13 wherein the tubular filament has a concentric hollow core of elliptical cross section.